A major interest of the Surgery Branch since 1960 has been the development of operative methods for the relief of obstruction in patients with idiopathic hypertrophic subaortic stenosis (IHSS). As of March 31, 1976, 132 patients have been operated upon and 106 have been evaluated in detail postoperatively. At operation a wedge of left ventricular septum is resected. After operation there was a distinct symptomatic improvement in all survivors. Cardiac catheterization has confirmed relief of obstruction in these patients. Nine patients died at the time of operation. Long-term followup has not demonstrated recurrence of obstruction. This continuing experience demonstrates that operation with left ventricular septal wedge resection in symptomatic IHSS patients with documented left ventricular outflow obstruction is low risk and provides symptomatic and hemodynamic improvement.